P1296

Code

CITROEN P — Powertrain

Injector 3 control malfunction

Brand: CITROEN

Type: P — Powertrain

Views: UK: 3 EN: 6 RU: 1

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Page language: EN

Read stored codes and freeze frame data with a scan tool; note freeze-frame and operating conditions
Visual inspection: check injector 3 connector, wiring harness, pin condition and routing for chafing or corrosion
Check fuses and relays for fuel/injector supply circuits
Backprobe injector connector with engine cranking/running to confirm presence of battery voltage at the supply pin
Use a noid lamp or oscilloscope on the injector control pin to verify pulsed signal from the ECU
Measure injector coil resistance and compare to manufacturer spec

Injector supply voltage (key ON): approximately battery voltage (~12V) at the injector supply pin
Injector coil resistance: consult vehicle spec — typical ranges: low-impedance injectors ~0.5–3 Ω, high-impedance ~10–18 Ω (varies by design)
Injector driver output: pulsed ground from ECU; pulse width varies with load and RPM; frequency proportional to engine speed
Noid lamp: should flash when engine is cranking/running if ECU is commanding injector
Oscilloscope waveform: clean square/rectangular pulsed ground with consistent pulse width; abnormal shapes indicate driver/ground issues

Retrieve and record DTCs and freeze frame data. Note any related misfire codes (e.g., P0303).
Perform a careful visual inspection of injector 3 connector, wiring harness and related grounds; repair any visible damage.
Verify battery voltage at the injector supply pin (backprobe) with ignition ON/engine cranking; check fuses/relays.
Backprobe the injector control pin while cranking/running: confirm pulsed signal using a noid light or oscilloscope. If no pulse, verify ECU driver circuit and wiring continuity to ECU.
Measure injector coil resistance (with injector disconnected) and compare to spec. Replace injector if resistance is out of range or intermittent.
Perform continuity and short-to-power/short-to-ground checks between injector control pin and ECU connector. Repair any wiring faults.
Swap injector 3 with a known-good injector from another cylinder (if practical). Clear codes and re-run: if code follows injector, replace injector; if code remains on cylinder 3, suspect wiring/ECU.
If wiring verifies good and a replacement injector does not cure the issue, consider ECU driver failure — consult manufacturer bulletin and only replace ECU after confirming harness and injector are good. Disconnect battery and follow vehicle-specific procedures before replacing ECU.
After repair, clear codes, perform functional test and road test to verify the fault is resolved. Re-check for related stored codes.

Connector corrosion or bent terminal at injector 3
Broken/shorted harness between injector connector and ECU
Injector coil open or low insulation (internal fault)
ECU output driver failed for injector 3 (more likely if fault follows wiring tests)
Lost power or ground to injector supply circuit

⚠️ Status

Injector 3 control circuit malfunction detected — possible open/short, connector or injector fault, or ECU driver failure.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0 - 3.0 hours

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